Fire protection systems commonly utilize a network of supply pipes for conducting a fire extinguishing medium, such as water, to a plurality of automatic sprinklers which may be arranged vertically, either in a pendent position or an upright position, or horizontally. Regardless of how the sprinklers are arranged, they must often be located a specific distance away from the supply pipes, for instance, when pendent sprinklers must be properly located with respect to a hung ceiling or a similar structure.
In the past, drop nipples connecting pendent sprinklers to a supply pipe system have been shortened or replaced with longer nipples to locate the sprinklers at a desired position. To avoid the difficulties and costs involved in shortening nipples which are too long and replacing nipples which are too short, adjustable length nipples have been developed. Such adjustable drop nipples are disclosed, for example, in Faulkner et al. U.S. Pat. No. 3,194,316; Van Houtte et al. U.S. Pat. No. 3,451,483; Adams, Jr. U.S. Pat. No. 3,529,671; Mears U.S. Pat. No. 3,675,952; Iasillo, Sr. U.S. Pat. No. 3,807,503; Horwinski U.S. Pat. No. 3,847,392; Jackson et al. U.S. Pat. No. 4,007,877; and Anderson U.S. Pat. No. 4,007,878.
In the sprinklers disclosed in all of these patents, except the Faulkner et al. and Iasillo, Sr. patents, stops are provided for limiting the downward adjustability of the nipples. However, the stops can not be released or disengaged to permit the disconnection of the nipples from a corresponding fluid supply pipe. Thus, an intermediate fitting must be removably coupled between the fluid supply pipe and the nipple to permit the disconnection of the nipple from the fluid supply pipe. The provision of such a fitting increases construction time and costs, as well as installation time and costs.
The Faulkner et al. and Iasillo, Sr. patents disclose pendent sprinklers having vertically adjustable drop nipples. However, during the vertical adjustment of the nipples, nothing prevents their accidental disconnection from a corresponding fluid supply pipe.